Cardaci G, Lambert J R, King R G, Onishi N, Midolo P
Department of Medicine, Monash University, Australia.
Antimicrob Agents Chemother. 1995 Sep;39(9):2084-7. doi: 10.1128/AAC.39.9.2084.
Amoxicillin when administered with gastric acid suppressors has been shown to be effective in eradication of Helicobacter pylori in 50 to 80% of subjects. The aim of this investigator-blind crossover study was to determine if gastric mucosal amoxicillin uptake was affected by increasing gastric juice pH. Fifteen male subjects (7 H. pylori positive and 8 H. pylori negative) were randomized to receive 150 mg of ranitidine twice a day, 300 mg of ranitidine twice a day, or no drug for 2 days prior to upper endoscopy. The last dose of ranitidine was given 60 min prior to upper endoscopy, and amoxicillin (500 mg) was given 30 min prior to upper endoscopy. The amoxicillin concentrations in mucosal biopsy samples, gastric juice, and serum were determined by a standard microbiological bioassay technique. Mean amoxicillin levels were greater in samples of antrum, fundus, and duodenum for volunteers who received no ranitidine than in those receiving 300 mg of ranitidine (P < 0.05) and those receiving 150 mg of ranitidine (P < 0.05 except for fundus). Amoxicillin levels in the antrum, fundus, and duodenum were negatively correlated with gastric juice pH (P < 0.005 for antrum; P < 0.001 for fundus and duodenum). There was no correlation between gastric juice pH and amoxicillin levels in either gastric juice or serum. The amoxicillin concentration in gastric juice was significantly higher with 300 mg of ranitidine than with no ranitidine (P < 0.05). Thus, lower gastric juice pH is associated with a higher rate of mucosal uptake of amoxicillin.
阿莫西林与胃酸抑制剂联用时，已证明在50%至80%的受试者中对根除幽门螺杆菌有效。这项研究者盲法交叉研究的目的是确定胃液pH值升高是否会影响胃黏膜对阿莫西林的摄取。15名男性受试者（7名幽门螺杆菌阳性和8名幽门螺杆菌阴性）被随机分为三组，在上消化道内镜检查前2天，分别接受每日两次150毫克雷尼替丁、每日两次300毫克雷尼替丁或不服用药物。雷尼替丁的最后一剂在进行上消化道内镜检查前60分钟给药，阿莫西林（500毫克）在进行上消化道内镜检查前30分钟给药。通过标准微生物生物测定技术测定黏膜活检样本、胃液和血清中的阿莫西林浓度。未接受雷尼替丁的志愿者的胃窦、胃底和十二指肠样本中的阿莫西林平均水平高于接受300毫克雷尼替丁的志愿者（P<0.05）和接受150毫克雷尼替丁的志愿者（胃底除外，P<0.05）。胃窦、胃底和十二指肠中的阿莫西林水平与胃液pH值呈负相关（胃窦P<0.005；胃底和十二指肠P<0.001）。胃液pH值与胃液或血清中的阿莫西林水平之间无相关性。300毫克雷尼替丁组的胃液中阿莫西林浓度显著高于未服用雷尼替丁组（P<0.05）。因此，较低的胃液pH值与阿莫西林黏膜摄取率较高相关。
